Going to piggy back off this response…I have a similar query in a different topic and haven’t got any response yet. Would be great to get your view on it! 
Basically, I’ve done a new FTP test using Tacx Vortex to record the power but also recorded the power from Assioma pedals on Garmin head unit (did not use Powermatch during test).
I got different results for each (higher power from the pedals) and unsure which FTP to use for next training block. I’m thinking I should use the higher one (given your response above which implies that using PowerMatch will make my sessions easier than they should be). Is that the correct way of thinking about it??